The current project was designed to further our knowledge of the nature of schizophrenia by a longitudinal investigation of the following questions about schizophrenic cognition: 1) Are there fundamental or primary features (which are always present) in schizophrenic thought disorders? Do specific types of thought disturbance differentiate patients into "true" schizophrenics and reactive psychoses? 2) What underlying factors might influence or determine thought disorders? 3) Are thought disorders primary symptoms which persist when the patient is in the recovery stage? What is the longitudinal history of a thought disorder? 4) Does thought pathology have prognostic significance, and predict the schizophrenic's subsequent clinical course? The research involves a multifaceted longitudinal investigation of schizophrenic thought disorders and other aspects of cognitive measures, taped interviews, patient self-ratings and staff behavioral ratings. These techniques are being used to assess idiosyncratic thinking, associative thinking, overinclusion, the abstract-concrete dimension, logical and autistic thinking, boundary disturbances, primary process drive-related content and other aspects of cognition. Several samples of scizophrenic and nonschizophrenic patients are being assessed longitudinally. Patients are being evaluated in the hospital at the acute stage, during partial recovery, and then followed up at varying time periods during the post-hospital period, in terms of potential disordered thinking, level of psychotic and neurotic symptoms, rehospitalizaton, personality variables, and social and work adjustment.